Dental instrument



April l947- D. REITER 2,418,316

DENTAL INSTRUMENT Filed Jan. 14, 1946 IIAOIIOIAYIIIIIIIIIIIIII PatentedApr. 1, 1947 DENTAL INSTRUMENT David Reiter, Woodside, Long Island, N.Y.

Application January 14, 1946, Serial No. 641,097

2 Claims.

The invention pertains to a dental instrument and more particularly to asprue holder or grip and guard.

In the art of dentistry it becomes necessary, under certain well knownconditions, to take an impression of a cavity previously drilled in atooth. Such an impression is made in wax which is employed as acomponent similar to a pattern. This pattern is then employed to make acavity in a plaster of Paris mold, so that the mold cavity correspondsidentically with the cavity of the tooth from which the wax impressiontook its configuration. The wax pattern is then removed. from theplaster of Paris mold and a precious or semi-precious metal, such asgold is, in a liquefied state, poured into the mold cavity, allowed tosolidify and subsequently removed from the mold. The resultant productis an inlay having such a configuration so as to fit snugly andaccurately into the tooth cavity. In the process of taking the waximpression hereinabove referred to, it is necessary to initially applyheat to the wax so as to render it easily workable, that is to say,plastic in nature to insure its reaching the innermost limits of thecavity and thus make a true and accurate impression of the cavity. Animplement known as a sprue-wire commonly referredto as a sprue isimbedded in the wax to remove the wax impression from the cavity. All ofthe preliminary steps are most usually conducted by. hand by a dentistwho, after removal of the sprue impression arrangement, sets it into asupport until such time the dentist wishes to continue with the processof forming th mold and take the subsequent steps above outlined.

With the above, therefore, as a background, it

,is an object of the present invention to provide an improved sprueholder or grip having means.

for positively and firmly holding a sprue.

Another object of the invention is toprovide an improved sprue holderhaving movably associated therewith, a guard arranged to surround thesprue in spaced relation thereto.

A further object of the invention is to provide, in a sprue holder orgrip. a slidably movable support capable of maintaining a sprue in aposition elevatedfrom a surface upon which the sprue holder may beplaced.

The above and numerous other objects will become apparent from thesucceeding description of an exemplified form of the inventionillustrated in the accompanying sheetof drawings wherein:

Figure 1 is a plan view of a sprue holder or support embodying thepresent invention.

Figure 2 is a side elevational view of the sprue, holder illustrated inFigure 1.

Figure 3 is an end elevational view of the sprue grip of Figure l; and

Figure 4 is an enlarged horizontal or longitudinal sectional view takenalong the lines 4-4 of Figure 2, looking in the direction indicated bythe arrows; a central portion of the sprue holder in this view being notshown.

Referring now in detail to the drawing wherein,

throughout the several views thereof, like reference charactersindicatelike, parts, the numeral l is employed to designatetin a somewhatgeneral manner, an improved sprue grip or holder illustrative of thepresent invention.

The sprue grip generally comprises a barrel or tubular housing or hollowshank 2 formed in part by a predetermined section of tubing 3 havinginterior threads at or adjacent each end thereof. Rotatably associatedwith one or a rear extremity 3a of the tube is a plug or closing piece 4having exterior threads to interlockingly engage the related interiorthreads'of the tubing and preferably has a portion 5 thereof ofsubstantially the same diameter as the outside diameter of the, tubingto present a somewhat even outer surface at this location. The portion 5is in abutting relation with the section of tubing so as to, in.

piece T and, like the closing piece, has an outer.

configuration such as to present, from all outward appearances, aforward continuation of the tubing. Extending, longitudinally, centrallyor axially through the closing piece is bore a, in axial alignment witha bore 9 in the head so that both bores commnuicate with the interior ofthe tubing (see Figure 4).

A clamping or gripping means is associated with the housing and, asexemplary of such a means, there is disclosed a rod or link l0 beingformed on a forward end thereof with a hook-like member H arranged tosurround orengage or hold a sprue l2. The trailing extremity of the rodis provided with exterior threads for a predetermined extent and for theaccommodation of a rotatable means or nut l3 having a knurled ex.-.-

terior as at M and arranged to abut the portion 5 of the housing orclosing piece. The knurled. surface, of course, is formed on the nut topresent asomewhat roughened surface for the successful manipulation ofthe nut.

From the above description it will be noted that the release actionthereof there is incorporated in the mechanism or instrument a releasingfeature and for the accomplishment of this purpose, the

rod, at a desired location intermediate its ends, has. a shoulder orabutment l5 secured thereto by any manner Or fashion. This abutment,located within the housing, is spaced a predetermined distance inwardlyof the housing from a related iner surface I B of the plug. Extending.around the rod and disposed between the shoulder I5 and surface [6 so asto react longitudinally thereagainst is a resilient means or coil orhelical spring l7. The coil spring has a sufficient compressive value tourge the rod toward the sprue engaging extremity of the housing upon aproper 1 manipulation of the nut I3.

It is the present intention or teaching that after a tooth cavity hasbeen prepared for an impression and warmedwax forced'into tooth cavityand carved as desired, a sprue is then placed in a clamped position inthe holder or grip.yThis sprue is heated in a flame with a guard I9pushed back as illustrated diagrammatically in Figure l'soas not to heatthe guard. The guard is then pushed back into a position approximatingthat as shown in full lines in Figure; 1 to guard'the hot'sprue fromburning,

a patient. The hot sprue is then imbedded into the wax pattern in thetooth. The sprue is chilled and thus clings to the wax pattern enablingthe operator to 'liftthe wax pattern out of the tooth. This process ispreferred since thereby there will be no likelihood of'an operator,

finding the-heated sprue hot to the touch, allowing the heated sprue tofall inthe mouth of a patient. After the wax impression is cooledsufliciently to insure its maintaining a true configuration of thecavity from which it was extracted and the heated sprue wire imbeddedinto thewax, is also chilled, the assemblage is moved in such a manneras to afford its removal from the mouth of a patient. It will be herenoted that the housing presents a suitablehandle and sufficient leveragefor an easy, positive and accurate removal of the wax impression fromthe cavity, thus eliminating the necessity of moving the sprue crosswiseof the cavity; which latter movement would destroy an otherwise true andaccurate impression.

When the wax impression is first removed from a cavity with the sprueimbedded-in it, it is cooled with a spray of cold water to allow it tobecome solidified thoroughly. The guard then protects thewax patternfrom coming in contact. with any object,- such as the hand of a dentistor a supporting surface upon which it might be laid. Great care must beexperienced in handling the sprue-impression assembly until such time asthe wax has been placed into a standard holder for investment. In orderto eliminate any possible defacing of the wax imp'ression, support meanshas been incorporated in the implement to maintain the sprue andparticularly the wax impression 'in an elevated posi- 4 tion. Toward theaccomplishment of this purpose, as well as another to be hereinafter setforth, a rest or guard I9 is associated with the barrel and comprises acollar I9a arranged to surround the barrel and slide with respectthereto. The collar may be split or formed as a continuous rin just solong as it presents a snug or sliding fit with the barrel. Extendingfrom the collar in an inclined direction away from the'barrel is aconnectingbar or link which vmay be an integral part of the collar or,as illustrated, be formed separately and secured by any manner to thecollar. An extremity of band or substantially semi-circular, hoop-likemember 2| which extends partially around or through the horizontalextended limits of the barrel as shown most clearly in Figure 3 of thedrawing. After an impression has been taken the rest may be rotatedabout the axisof the barrel thereby placing the impression within theprotective limits of the rest and the implement may then be set upon asupportingsurface as indicated diagrammatically in Figure 3 only of thedrawing by the reference character 22. It willhere be noted that theimpression, indicated diagrammatically as at 23 is supported out ofcontact with any other object to prevent breakage'or injury to thepattern and the hooplike member presents transversely spaced, curved,sturdy legs 24. If one desires, the sides of the wax pattern is stillprotected. I v

Another feature is attributed to the rest or guard andthat is, it willfunction as a' means for holding a patients cheek or tongue out of theway, while-the process of inserting a hot sprue into an impression isbeing performed, preventing burning of -a patient. It will also be notedthat this novel sprue grip is used to place the free end of the spruewire into-a wax portion of the standard holder. Then the nut I3 isturned to release-the sprue and wax pat- .tern in the holder over whicha casting ring is placed and into which-"ring the investment is poured.

From the above it will be noted that various changes and alterations maybe made to the illustrated and described construction without departingfrom within the spirit of the invention and scope of the appendedclaims. I claim: l 1. In a sprue holder, the combination of, a tubularbarrel provided at one end with ahead piece and at another end with aplug, a rod extending through said barrel, head piece and plug,hook-like means formed integrally on' oneend of said rodbeyond saidheadpiece and-arranged to clamp a sprue to said head piece,- a nutrotatably mounted on said 'rod and in'bearing relation with said plugfor drawing said hook-like means toward said headpiece, an abutmentformed onsaid rod intermediate the ends'thereof, coil spring meanswithin said barrel and acting a'gainst said abutment for urging saidhook-likemeans away from said head piece upon a proper manipulation ofsaid nut, and guard means s'lidably movable on said barrel and havingsp'a'ced legs for maintaining said sprue'in elevatedposition; l

2. In a sprue holder, "he combination of, a tubular barrel having at oneend a. head piece and at another end a plug, a rod extending throughsaid barrel, head piece and mg'and freely movable relative thereto, :a,bent extremity formed'on one end of-s'aid rod beyondfsaid head guard canrest on a supporting surface and the piece and arranged to clamp a sprueto said head piece, a nut .threadedly mounted on said rod and in bearingrelation with said plug for drawing said bent extremity toward said headpiece, an abutment formed integrally on said rod intermediate said headpiece and plug, a coil spring within said barrel and acting against saidabutment and plug for urging said bent extremity away from said headpiece upon a proper manipulation of said nut, and guard means slidablymounted on said barrel; said guard means having an arcuate intermediateportion terminating in spaced legs the latter of which are arranged as asupport for maintaining said sprue in an elevated position.

DAVID REITER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

